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Characterization of HD 206893 B from Near- to Thermal-infrared

Meshkat, Tiffany and Gao, Peter and Lee, Eve J. and Mawet, Dimitri and Choquet, Élodie and Ygouf, Marie and Patel, Rahul and Ruane, Garreth and Wang, Jason and Wallack, Nicole and Absil, Olivier and Beichman, Charles (2021) Characterization of HD 206893 B from Near- to Thermal-infrared. Astrophysical Journal, 917 (2). Art. No. 62. ISSN 0004-637X. doi:10.3847/1538-4357/ac09ed.

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HD 206893 B is a brown-dwarf companion orbiting inside the debris disk of its host star. We detect the brown dwarf in the Ms band using the Keck/NIRC2 instrument and vortex coronagraph. We measure its magnitude to be M_s 12.97_(-0.11)^(0.10). It is at an angular separation of 0farcs22 ± 0farcs03, and a position angle of 39.6° ± 5.4° east of north. Using this Ms-band measurement and the system age, we use three evolutionary models to estimate the mass to be 12–78 M_(Jup). We analyze the atmospheric properties from 1–5 μm using a grid of simulated atmospheric models. We find that a sedimentation flux f_(sed) value ∼0.2 provides the best fit to the data, suggesting high vertically extended clouds. This may be indicative of high-altitude grains or a circumplanetary disk. Our model radii and luminosities for the companion find the best fits are ages of <100 Myr and masses <20 M_(Jup), consistent with our mass estimate from the evolutionary models using the Ms-band data alone. We detect orbital motion of the brown dwarf around the host star in comparison to the discovery image and derive orbital parameters. Finally we analyze how the companion brown dwarf interacts with the debris disk by estimating the location of the chaotic zone around the brown dwarf using values derived from this study's estimated mass and orbital constraints. We find that the collisions within the debris belt are likely driven by secular perturbations from the brown dwarf, rather than self-stirring.

Item Type:Article
Related URLs:
URLURL TypeDescription
Meshkat, Tiffany0000-0001-6126-2467
Gao, Peter0000-0002-8518-9601
Lee, Eve J.0000-0002-1228-9820
Mawet, Dimitri0000-0002-8895-4735
Choquet, Élodie0000-0002-9173-0740
Ygouf, Marie0000-0001-7591-2731
Patel, Rahul0000-0002-5025-6827
Ruane, Garreth0000-0003-4769-1665
Wang, Jason0000-0003-0774-6502
Wallack, Nicole0000-0003-0354-0187
Absil, Olivier0000-0002-4006-6237
Beichman, Charles0000-0002-5627-5471
Additional Information:© 2021. The American Astronomical Society. Received 2020 December 7; revised 2021 June 5; accepted 2021 June 8; published 2021 August 17. We thank the anonymous referee for their helpful suggestions that improved this paper. We thank our Keck/NIRC2 support staff, without whom the data could not have been obtained: Cynthia, Terry Stickel, Greg Doppmann, Bruno Femenía Castellá, and Carlos Alvarez. P.G. and J.W. acknowledge support from the 51 Pegasi b Fellowship sponsored by the Heising-Simons Foundation. P.G. is also supported by NASA through the NASA Hubble Fellowship grant HST-HF2-51456.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. Part of this work has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No. 819155). This research has made use of the SVO Filter Profile Service ( supported from the Spanish MINECO through grant AYA2017-84089. The plots presented in this paper we created using matplotlib in python (Hunter 2007). The data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and NASA. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Group:Astronomy Department, Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Heising-Simons Foundation51 Pegasi b Fellowship
NASA Hubble FellowshipHST-HF2-51456.001-A
European Research Council (ERC)819155
Ministerio de Economía, Industria y Competitividad (MINECO)AYA2017-84089
W. M. Keck FoundationUNSPECIFIED
Fonds de la Recherche Scientifique (FNRS)UNSPECIFIED
Subject Keywords:Brown dwarfs; Debris disks; Direct imaging; Coronagraphic imaging; Astrometry; Exoplanet atmospheres
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Brown dwarfs (185); Debris disks (363); Direct imaging (387); Coronagraphic imaging (313); Astrometry (80); Exoplanet atmospheres (487)
Record Number:CaltechAUTHORS:20210914-225358608
Persistent URL:
Official Citation:Tiffany Meshkat et al 2021 ApJ 917 62
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110890
Deposited By: George Porter
Deposited On:15 Sep 2021 22:13
Last Modified:15 Sep 2021 22:13

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